Current mode DC/DC converter-LT8361 and Evaluation Kits-DC2599A

Published time: 2018-12-05

The LT8361 is a current mode DC/DC converter with a 100V, 2A switch operating from a 2.8V to 60V input. With a unique single feedback pin architecture it is capable of boost, SEPIC or inverting configurations. Burst Mode operation consumes as low as 9μA quiescent current to maintain high efficiency at very low output currents, while keeping typical output ripple below 15mV.

An external compensation pin allows optimization of loop bandwidth over a wide range of input and output voltages and programmable switching frequencies between 300kHz and 2MHz. A SYNC/MODE pin allows synchronization to an external clock. It can also be used to select between burst or pulse-skip modes of operation with or without Spread Spectrum Frequency Modulation for low EMI. For increased efficiency, a BIAS pin can accept a second input to supply the INTVCC regulator. Additional features include frequency foldback and programmable soft-start to control inductor current during startup.

Evaluation Kits suitable for LT8361

Demonstration circuit 2599A features the LT8361 in a SEPIC configuration. It operates with a switching frequency of 400kHz and is designed to convert a 4.5V to 48V source to 24V, with up to 600mA output current (depending on input voltage).The LT8361 can operate with inputs as high as 60V. However, in this demo circuit, the input is limited by the voltage rating of the input capacitors.

The demo board contains a selectable jumper, JP1, to aid in the selection of the desired Sync pin mode of operation. The default setting is Burst Mode® operation.This layout is optimized for good EMI performance and small solution size. Input and output filters and an optimized power switching loop, comprised of C20 and C21 are necessary to pass CISPR 25 Class 5 emissions, and are added by default. These components can be excluded in applications not requiring noise immunity.